Almost all the services offer some sort of page builder that makes it easy to drag and drop to build your page. These are great for getting started, but they often lock you into the service. Most page builders are proprietary to the service, or don't create HTML that's portable enough to be easily moved to another service if you decide it's necessary.
You are made to choose from a selection of templates and later get to edit them to your liking. But not everyone enjoys this! Some people prefer to have more customization and perhaps use a different content management systems like WordPress. For these people, a website builder is not a preferable choice, as they won’t develop the skills needed to make a professional page.
Many services offer a low "starting price," but require you to prepay for two or three years of service to get that price. After the promotional period, the renewal price for some services can be two, three, or even four times the initial promotional pricing. While the initial deal might be incredible, the cost of transferring your site (or paying the added fee) in a couple of years may be something to consider.